polymer: setting individual array elements not working

Binding specified by path eq [[test.0.value]] or dom-repeat have nothing in common with actual data in model. Given:

         properties: {

           test: {
             type: Array,
             value: [{value: 0}],
             notify: true
           }
         },

         ready: function() {
           this.unshift('test', {value: 1});
           this.set('test.0.value',     2);
           this.set('test.0',   {value: 3});
           this.set('test.0.value',     4);
           this.push('test',    {value: 5});
           this.$.model.innerText = JSON.stringify(this.get('test'));
         }

        <header>static path [[test.0.value]]</header>
        <div>[0] <span>[[ test.0.value ]]</span></div>
        <div>[1] <span>[[ test.1.value ]]</span></div>
        <div>[2] <span>[[ test.2.value ]]</span></div>

        <header>dom-repeat</header>
        <template is="dom-repeat" items="[[test]]">
          <div>
            [<span>[[index]]</span>] = <span>[[item.value]]</span>
          </div>
        </template>

        <header>actual model</header>
        <div id="model"></div>

results in

static path [[test.0.value]]
[0] 3
[1] 2
[2]
dom-repeat
[0] =
[1] = 0
[2] = 5
actual model
[{"value":4},{"value":0},{"value":5}]

http://plnkr.co/edit/RFWLVhQ5yZ5E4sQYpLJG?p=preview